The present invention relates to the processing and handling of diagnostic video image data. The present invention finds particular application in conjunction with vascular diagnostic imaging systems and will be described with particular reference thereto. However, it is to be appreciated, that the invention may also find application in conjunction with the handling of other diagnostic image data.
In a vascular diagnostic system, an x-ray source is commonly disposed on one side of the patient and an image intensifier is disposed on the other side of the patient. The image intensifier converts the x-rays which are transmitted through the patient and strike the image intensifier into a corresponding optical image. That is, an optical or light image is generated in which the intensity of light at each point of the image varies in accordance with the intensity of radiation which passed through the patient and struck the image intensifier. A beam splitter is mounted to the image intensifier for selectively directing the optical image to one or more cameras. The cameras typically include video or electronic cameras and film cameras for generating single frame images and motion picture or video images.
The video images from the electronic camera are typically acquired and processed by a digital image processing system. Each diagnostic suite includes appropriate video monitors for displaying the digitally processed video images and a VCR for recording video electronic images. The VCR playback images may also be displayed in the diagnostic suite or on a control room reference image monitor. In addition to the current or live data from the video camera, the diagnostician commonly wishes to view one or more reference images. The reference image may be an image taken several minutes earlier, an image from an earlier examination, or the like. One common application of the reference image is in conjunction with radiation opaque dyes. After a reference image is recorded, the patient is injected with the radiation opaque dye. Both the live images and the recorded reference images are then displayed on the live and reference image monitors, respectively. The two images are to be compared for diagnostic purposes.
One of the problems with such systems is that the various electronic image signals do not have the same bandwidth. Typically, the live image is a high resolution image of 1024.times.1024 pixels or better, displayed at 30 or higher fps, in either progressive or interlace format. An S-type VCR records or plays back images with a much lower resolution, e.g. about 512.times.512 pixels per image at 30 fps interlaced. These lower resolution images are conveyed with a lower bandwidth signal. Typically, the VCR playback images are displayed on the reference image monitor which is usually dual rate type, capable of displaying both high resolution and S-type VCR images.
Typically, the output of the electronic camera is digitized and conveyed to a digital processing board which generates a low bandwidth downscan signal for recording on a VCR and a high bandwidth live signal for display on a high resolution live image monitor. Further, the digital processor board converts reference images stored in a video memory into high bandwidth reference signals for display on the reference image monitor.
Typically, a system may include more than one diagnostic imaging room as well as a central control console. The central control console and the digital processor boards are relatively expensive. Rather than provide each room with its own digital processor board, a significant cost savings can be achieved by sharing the digital processor board. This requires a relatively complex switching system for switching the camera outputs and the VCR outputs from each room to the digital processor board and the outputs from the digital processor board back to the appropriate monitors and VCRs in each room and the control console.
In a vascular diagnostic system with a large number of rooms, either a larger number of digital processor boards are required or an increasingly complex switching system. One of the problems with the prior art is that when a hospital adds additional rooms, a new switching system is required which can switch the digital processing board among a larger number of rooms. Analogously, manufacturers must inventory a large number of different size switching systems in order to accommodate the varying number of rooms which hospitals might order.
The present invention provides a new and improved daisy chain video switch system which overcome the above-referenced problems and others.